Oral Presentation Clinical Oncology Society of Australia Annual Scientific Meeting 2017

Trends in stage-specific breast cancer incidence in New South Wales, Australia: insights into the effects of 25 years of screening mammography (#93)

Gemma Jacklyn 1 2 , Kevin McGeechan 3 , Stephen Morrell 4 , Les Irwig 3 , Nehmat Houssami 3 , Katy Bell 3 , Alexandra Barratt 1
  1. Sydney School of Public Health, Wiser Healthcare, The University of Sydney, NSW, Australia
  2. University of Sydney, University Of Sydney, NEW SOUTH WALES, Australia
  3. Sydney School of Public Health, University of Sydney, Sydney, NSW, Australia
  4. School of Public Health and Community Medicine, University of New South Wales, Sydney, NSW, Australia


To describe temporal trends in the incidence of stage-specific breast cancer in New South Wales, Australia, between 1972 and 2012.


Observational study of all women who received a diagnosis of BC from 1972-2012 as recorded in the NSW Cancer Registry, a population based registry with almost complete coverage and high rates of histological verification. We analysed trends in stage-specific incidence before screening and compared them to periods after screening began. Our primary group of interest was women in the target age range of 50-69 years, though trends in women outside the target age were also assessed.


Screening was not associated with lower incidence of late-stage BC at diagnosis. Incidence for all stages remained higher than prescreening levels. In women aged 50-69 years, the incidence of carcinoma in situ (CIS), localised and regional BC has more than doubled compared to the prescreening era, with incidence rate ratios ranging from 2.0 for regional (95% CI 1.95-2.13) to 121.8 for CIS (95% CI 82.58-179.72). Before the introduction of screening there was a downward trend in distant metastatic BC incidence, and after the introduction of screening there was an increase (IRR 1.8; 95% CI 1.62-2.00). In women too young to screen the incidence of late-stage BC at diagnosis also increased, whereas localised disease was stable.


The incidence of all stages of BC has increased over the past forty years, with the greatest rise seen during the established screening period for women aged 50-69 years. Our findings suggest that some of the expected benefits of screening may not have been realised and are consistent with overdiagnosis.